1. Field of the Invention
The present invention relates to fluid flow equipment, and more particularly, to fluid transfer controlling equipment such as compressors, pumps, blowers, and power generation devices (e.g., turbochargers and turbo-engines).
2. Description of the Related Art
The following descriptions and examples are not admitted to be prior art by virtue of their inclusion within this section.
Fluid transfer controllers are used for a variety of functions, including but not necessarily limited to compressing and pumping fluids as well as converting energy from flowing fluids for power generation devices. Exemplary applications for fluid transfer controllers with one or more of such functions include aircraft jet engines, industrial gas compressors, pipeline transports, refrigeration systems, as well as several others. In general, fluid transfer controlling equipment (referred to hereinafter as “fluid transfer controllers” and “fluid flow controllers” interchangeably) may refer to apparatuses that direct, manage, and/or influence the course of liquids, gases, liquid-gas combinations, and/or combinations of solids with liquids and/or gases. Some fluid transfer controllers have components which are similar in design. For instance, a common component within some fluid transfer controllers is a centrifugal rotor. A centrifugal rotor generally includes blades extending radially outward from a central component, the gaps between the blades defining the fluid flow path through the rotor. During operation, fluid typically enters the centrifugal rotor near the central component in a direction substantially parallel to its rotational axis, moves through the gaps between the blades by centrifugal force, and exits the rotor in a direction substantially perpendicular to the rotational axis of the rotor. The fluid is then generally directed into a collector (e.g., a volute) and subsequently through an outlet of the fluid transfer controller.
By appropriately rotating the rotor, the blades of the rotor may accelerate the fluid, allowing the fluid to exit the rotor assembly with increased velocity and possibly increased pressure. As such, the degree of fluid flow acceleration in a centrifugal rotor assembly is largely affected by the size and speed of rotation of the rotor as well as the orientation of the blades on the rotor. Unfortunately, however, the extent to which the orientation, size, and speed of the rotor blades may be effectively manipulated to enhance fluid flow acceleration is limited. In an attempt to circumvent this problem, many fluid transfer system designers arrange a plurality of fluid transfer controllers in series to obtain greater fluid velocity and/or pressure rises than those that may be obtained from a single fluid transfer controller using the same type of rotor (i.e., a rotor of the same size and having similar blade configuration). In particular, designers often integrate conduits between outlets and inlets of distinct fluid transfer controllers such that fluid may be successively routed through each without interruption.
Fluid transfer systems employing serially arranged fluid transfer controllers to increase fluid flow velocity and/or pressure, however, are not without their own shortcomings. In particular, transporting a fluid between controllers without significantly diminishing its velocity or pressure is difficult and, thus, the efficiency of fluid transfer controllers arranged in series is often less than a single fluid transfer controller with the same type of rotor. In addition, fluid transfer controllers arranged in series are substantially larger than a single fluid transfer controller with the same type of rotor, increasing the size of the fluid transfer system. In some applications, small fluid transfer systems are needed due to space constraints and, thus, employing a fluid transfer system with serially arranged fluid transfer controllers may not be an option in some cases. Furthermore, the noise generated from fluid transfer systems having serially arranged fluid transfer controllers is compounded relative to the number of fluid transfer controllers employed. Limiting noise generation, however, is beneficial in many applications, particularly when used in areas of human occupancy.
Moreover, initial fabrication costs as well as the cost and time required to maintain fluid transfer controllers arranged in series are typically proportional to the number of fluid transfer controllers employed. In some cases, costs and maintenance downtime are further increased when a rotational shaft is shared among fluid transfer controllers in series. In particular, a shaft providing rotational motion for rotors of multiple fluid transfer controllers in series needs to be substantially longer than those used for single fluid transfer controller systems. Longer shafts typically require more precise dimensions and are generally more difficult to maintain than shorter shafts. As a consequence, the inclusion of a long shaft may substantially increase costs and maintenance downtime for systems having fluid transfer controllers arranged in series.
Accordingly, it would be desirable to develop a compact fluid transfer controller that increases the range of fluid flow acceleration as compared to conventional designs. It would be further advantageous for such a fluid transfer controller to limit the level of noise generated therefrom.